An embodiment relates generally to vehicle positioning systems.
Global Positioning System (GPS) or other Global Navigation Satellite System (GNSS) receivers operate by tracking line of sight signals. These receivers typically require at least four or more satellites to be continuously available in an unobstructed line of sight of a satellite receiver on a vehicle. Due to natural and man-made obstructions (e.g., buildings) or natural obstructions (i.e., dense tree cover), the theoretical minimum number of satellites required to accurately determine a position of the satellite receiver may not be available under certain conditions. It is well known that GPS positional errors may be as great as 30 meters. While such errors may result in minor inconveniences in navigation as to whether the vehicle is exactly at a location (e.g., intersection), greater issues are present when systems such as lane centering or speed control is used when the vehicle is traveling through a curved portion of the road. If an automated vehicle system is controlling the speed or the centering of the vehicle and the system relies on the position on the GPS position of the vehicle, then estimating that the vehicle is on a linear portion of the road as opposed to a curved portion of the road may have negative implications.